These knobs will fit all C5 models made prior to 2006, and all 2006 and later models EXCEPT those with black Phillips factory collimation screws. The black Phillips screw model requires C5 metric knobs. Check that our screw threads match the factory screw threads before installing.

The factory dust cover will fit normally with Bob's Knobs installed.

Some telescope versions have a small plastic cover over the factory collimation screws. This cover must be removed and set aside when Bob's Knobs are installed. The cover is cosmetic only and will not affect operation of the scope.

These knobs will fit all C5 models made prior to 2006, and all 2006 and later models EXCEPT those with black Phillips factory collimation screws. The black Phillips screw model requires C5 metric knobs. Check that our screw threads match the factory screw threads before installing.

The factory dust cover will fit normally with Bob's Knobs installed.

Some telescope versions have a small plastic cover over the factory collimation screws. This cover must be removed and set aside when Bob's Knobs are installed. The cover is cosmetic only and will not affect operation of the scope.